Automatic lathe



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C. M. BOSWORTH AUTOMATIC LATHE Original Filed Dec. 13, 1934 15 Sheets-Sheet 14 R O T N E V m Oct. 7, 1941. c. M. BOSWORTH AUTOMATIC LATHE Original Filed Dec. 13, 1934 l5 Sheets-Sheet l5 Patented Oct. 7, 1941 Search Rot t AUTOMATIC LATHE Cyrus Milburn Bosworth, Rochester, N. Y.

Application December 13, 1934, Serial No. 757,316 Renewed June 25, 1940 32 Claims.

This invention relates to automatic lathes used for machining metal parts from bar stock, and known to the trade as hydraulically operated automatic screw machines.

The object of the invention is to provide an improved machine of this class.

One object of the invention is to provide a hydraulic control in which all the movable parts are so interlocked that they will synchronize and thus avoid interference with one another.

Another object of the invention is to provide an accurate control for the automatic return of the slides after they have finished forming to desired diameters and lengths. This control will also provide for adjustment to compensate for inaccuracies in the various spindles.

A further object is to provide an automatic lathe of novel construction having less parts, smoother and faster action and greater rigidity.

Another object is to provide a rigid and simple cross slide construction.

A further object is to provide a new type of tool slide and an improved method for its support.

Another object is to provide a simple method of hydraulically indexing the work spindle carrier, opening and closing the work spindle chuck, the feeding of the bar stock, the pulling of the work spindle carrier lock bolt and the synchronization of these actions. Y

A further object is to provide a rigid bed construction that will allow ample chip space, the ready removing of the chips while the machine is in operation and permit use of a small splash guard that will keep the outside of the machine dry and clean and will -allow the Operator to stand close to the tools; also that will provide a machine of exceptionally low height, occupying a small floor space, yet containing the driving motor within the outline of the machine.

Another object of this invention is to provide a hydraulic fluid reservoir that extends above all pipe connections or sliding joints, thus providing against siphoning of the fluid and thereby preventing air entering the circuit, which would cause damage as will be explained later.

A further object is to provide a convenient method of adjusting the length of stock to be fed out.

Another object is to provide a method of feeding the stock so that the feed tubes will not protrude out any distance from the spindle except during stock feed.

Another object is to provide a means to hold chuck and feed thimbles in their proper place when operating. these retainers being readily raised or swung out away from the feed and chuck thimbles, thus allowing all the work spindles to be stocked at one time. This will save considerable time at each loading of the machine.

A further object is to provide for the counterclockwise rotation of the work spindle carrier so that the last operation ls the cut-on position, that is in the lower front position, thereby making it easy to catch the finished work as it is cut off, placing the most troublesome tools such as taps, dies and reamers in the front of the machine where they can be seen and given attention. In fact, it will seldom be necessary to go to the rear of the machine.

Another object is to provide a swinging gage stop that is out of the way when the tools move forward and not in the path of the chips in their descent into the chip pit and the synchronization of its operation.

A further object is to provide a convenient method of mounting any auxiliary tool slide attachments, such as a threading attachment, high speed drilling and accelerated reamer in any of the tool positions without making troublesome pipe connections or without the use of a complication of shafting and gears.

Another object is to provide a stock reel indexing means which gets its power directly from the indexing mechanism and not thru the work spindle carrier, and its exible drive so that stock reel need not be exactly in line with work spindle carrier.

Another object is to provide a Work spindle mounting and also a work spindle carrier mounting in which all the end thrusts in either direction for both work spindles and work spindle carrier is taken close to the tools, thus eliminating variation in length o! the work due to diil'erence in temperature ofthe spindle head parts.

A further object is to provide a throttle valve that will vary its opening or throttling eii'ect with any change in fluid tempera-tures so as to keep the feed rate constant when the machine is set up at a deiinite rate of feed.

The above and other objects will more fully appear from the following description and accompanying drawings and will be especially pointed out in the appended claims.

In the accompanying drawings and forming parts of the specications:

Fig. 1 is a front elevation of the hydraulically operated multiple spindle screw machine.

Fig. 2 is a plan view of the same, with spindle guard removed.

Fig. als a vertical longitudinal section through the-center line of the machine and work spindle carrier, showing all parts in their respective proper positions during the indexing of the work turret.

Fig. 4 is a left end elevation, in which part of end of machine is removed to show the indexing mechanism, stock feed shoe slide, chuck operating shoe slide and lock bolt operating mechanism.

Fig. 5 is a vertical cross section on the line indica-ted at 5--5 in Fig. l through the main slide looking in the direction of arrows showing bed construction.

Fig. 6 is a right end elevation showing method of mounting motor, iiuid pumps and method of drive to change gears for driving work spindles.

Fig. '7 is an enlarged section through work spindle carrier and through one work spindle showing method of taking thrust of work spindle and work spindle carrier. The lower half of section is one through work turret between Work spindles.

Fig. 8 is an enlarged vertical section through the main slide showing the connection of tool slide to tool slide piston.

Fig. 9 is an enlarged section through main tool slide support showing method of retaining slide and .preventing its rotation.

Fig. 10 is an enlarged section taken on line Iii-I0 in Fig. 1 showing arrangement of cross slides and their stops, the shape of .the tool slide or main slide and the method of holding main slide tools and the gage stop mechanism.

Fig. 11 is an enlarged front elevation of one of the cross slides showing its throttle valve.

Fig. 12 is an enlarged top view of cross slides with one cross slide in section showing its piston.

Fig. 13 is an enlarged end view of cross slide throttle and cam.

Fig. 14 is an enlarged front elevation ofv throttle mechanism.

Figs. 15', 15A and 15B comprise the hydraulic circuit diagram showing how the parts are made to synchronize, the method of control of the feed, rapid traverse and reverse of the slides, the hydraulic index, stock feed chucking mechanism and swinging gage stop.v

Fig. 16 is an enlarged section of the throttle valves.

Fig. 17 is an enlarged cross section at right angles to the axis and through the throttle portion of the throttle valves.

Fig. 18 is an enlarged vertical section through the index piston showing index gear, wedge pulling and chucking mechanism and chuck thimble retaining guards.

Fig. 19 is an enlarged vertical section through the stock feed slide showing stock feed shoe, slide and cam, and stock feed thimble retaining guards.

Fig. 20 is an enlarged plan view of indexing, wedge operating, chuck operating and stock feeding mechanisms.

Briefly the invention includes a rotatable intermittently operated work spindle carrier cylinder, shown in the present instance carrying four work spindles and hydraulic means for indexing it intermittently, and an end working main tool slide movable axially towards and away from the work turret, and hydraulic means for operating it, together with cross slides and swinging gage stop and hydraulic means for operating them and means for interlocking all parts so that they will synchronize.

It will be seen by referring to the drawings that a large multiplicity of cams, levers, gears, clutches and shafts ordinarily used in this type of machine have been eliminated. In a hydraulically operated machine it is a simple matter to synchronize the starting of the several slides at any determined time by having their respective valves operated by cams located on a common cam shaft, or cams on one of the slides, but it is very diillcult to control the time when they will finish their work and return, this time being dependent on the rate of feed of their respective slides. so unless the time of indexing the turret and/or the feeding of the stock and the starting of all slides is not controlled by the return of each and every slide, or in other words if all the slides are not back because of too slow a rate of feed or hard spots in the material or dull tools, then there will be interference and damage to the machine and tools.

This invention provides for such interlocking that the turret cannot index until all tools are back, and also that no tool can go forward again until the index is completed. The index includes the opening and closing of the chuck, the feeding and the gaging of the stock. After the work turret is indexed and the gage stop swung out of the way, all tools start forward in rapid traverse until the tools are close to the work, at which time the speed drops to the desired rate of feed for each tool slide, continuing until the end of the stroke, where they dwell until exact dimensions are reached on the work and then individually trip into rapid traverse in the reverse direction and return to the starting position. where they wait until all the other slides are back.

When the last slide is back, then the gage stop will swing up and the chuck in lower front position will open and the turret will index. During index the stock will feed out against swinging gage stop. After the index is completed and the chuck is closed, the gage stop is moved out of the way, and then all the tool slides move forward.

It is thus seen that all hydraulic elements are interlocked so that if one element fails to function due to any cause, then all elements, will stop until interference is removed.

The machine in which the above described interlocking means is used together with many other important improvements comprises a bed casting I of a box section, Figs. 1, 2, 3, 4, 5 and 6, on the top of which are cast integral with it three bearings.

The largest bearing located at the left end with the cap 2 is a bearing housing for work spindle carrier. The smaller bearing and cap 3 located to the right of the center of the bed is a bearing housing for the tool slide and main slide. The bearing 4 with no cap, located at extreme right, is a housing for the main slide piston l. All three bearings being integral with bed, are bored in line in one setting thus insuring perfect and permanent alignment at low cost. The caps 2 an'd 3 are used to facilitate the fitting and assembling.

There is a large opening 6, Figs. 2 and 5, in the top of the bed between the turret bearings and the main slide for the passage of chips to the inside of the bed, and openings in front, rear and at both ends for the removal of the chips.

There is also a large opening 1, Figs. 2 and 3, in the rear at the right end of bed for convenience Search Room of piping up the machine, and for mounting the motor and pumps. In addition, there is a small wall or bead 8, Figs. 2 and 5, on the upper edge of bedm each side of the work turret housing, which in conjunction with a small guard 9 keeps the oil and chips on the inside of the machine and thereby keeping the outside of the machine clean.

The extreme left end of the bed, Fig. 1, has a fiat machined surface I which holds the base I I for the indexing stock feed and chuck operating mechanisms (see Figs. 1 and 3) and also on which is mounted the stock reel support I2.

The work spindle carrier or Work turret I3, Fig. 7, is located in housing 2 for intermittent rotation and indexing, and is bored centrally and axially for the reception of the tool slide supporting sleeve I4. This sleeve is heldv fast and is part of the work spindle carrier extending into the bearing of the tool slide. This sleeve is bored centrally to receive a work spindle driving shaft I5, which is driven by a motor A, Figs. 2 and 3, located in the rear right end of the bed, through change gears as will be explained later. 'Ihe central bore of the work spindle carrier is also bored for bearings for the spindle driving shaft. Within the work spindle carrier are also several holes bored parallel with the central bore and the center line of the Work spindle carrier and at equal distance from each other for the housing of the work spindles I6, four of which are shown in this illustration.

The work spindles are of somewhat standard design, the bar of stock I1, Fig. 7,'beng held by push-out chuck I9 which is held against nut |9 threaded in the work spindle. The chuck is made to grip by having its cone surface telescoped by the pusher 20 which is pushed in turn by push tube 2|. This tube is pushed forward by thrust collar 22 which in turn is pushed by the chuck fingers 23 which are pivoted at 24. The outer ends of the fingers are forced up on the larger diameter of chuck thimble 25 when the bar is chucked from lower front to lower rear position. The chuck thimbles are held in this position except when chuck is open for feeding stock by the front and rear sections H and I|5b respectively of a retainer ring, which sections are integral with guards ||5d and |I5c respectively, there being four guards. the front and I I5c in the rear. Both are around the chuck thimbles, yas shown in Fig. 18.

Guard IIId is in front and IIIic is in the rear and both are around the feed thimble, as shown by Fig. 19. Shoe 41c which is integral with index slide 41 also retains chuck thimbles in lower rear position.

The chuck thimble is actuated by chuck shoe which is integral with chuck slide 21, Figs. 4 and 18, which is in turn actuated by 'chuck piston 28, Figs. 3, 4, 19 and 20. The chuck piston rod has two collars 29 fastened securely to its outer end. These collars 29 straddle a cross extension 21b which is integral with chuck slide 21, the rod extending through an elongated slot 21, Figs. 4 and 18. The hydraulic action of the chuck piston causes the chuck slide to move longitudinally of the machine and the work to be chucked. The timing of this action will be described in connection with the explanation of the index mechanism with which it is interconnected.

The stock is fed in the work spindles by a standard constructed feed tube 30, Fig. 7, and feed thimble 3|, but the feed tube and thimbles llsdism are heldin the forward or in toward the machine position by a segment of a ring retainer I I6'l and IIBh located also on guard ||6 and IIBd except during the return of the stock feed tube and during the actual stock feeding which takes place during index. The timing of these actions of the feeding stock will also be described in connection with the indexing with which it is also interconnected. Suflice to say at this time that the stock feed thimble 3| is actuated by stock feed thimble shoe 32, Figs. 1, 2, 3, 19 and 20, which is integral with stock feed slide 33, Figs. 2, 3, 19 and 20, which is moved longitudinally of the machine by the adjustable cam 34, Figs. 2, 19 and 20, during the index of the work turret I3. The Work spindles I6, Fig. 7, are mounted in ball bearings and 36 which in turn are mounted in the work spindle carrier. The front spindie bearings 35 take all the end thrusts in either direction, the rear spindle bearings 35 take only radial load and are free to float. The front bearing set have their inner races clamped tightly to the spindle by means of the spindle nut 35l and a spacer tube 35h. The outer races of bearing 35 fit against the shoulder 35c in the work spindle carrier. An adjusting nut 31 threaded in to work spindle carrier takes up the play in the front spindle bearings and serves as a splash guard around nose of spindle. A lock nut 31* prevents the loosening of the adjusting nut. The above construction avoids variation in the length of work due to the change of length of spindles caused by expansion due to temperature rise.

The work spindle carrier is restrained from end motion by means of a flange 38 at the tool end of the cylinder. This flange bears against work spindle carrier housing 2. The thrust from end working tools such as drills will be taken against this housing, any end play and thrust in the opposite direction is taken by brass shoes 39 located between the flange and cross slide housing 40. These shoes are held up against the fiange on work spindle carrier by means of screws 4I, Fig. 7. This construction will safeguard against unequal expansion of work spindle carrier and work spindle carrier bearing. The work spindle carrier has recesses 42 to allow for the work spindle driving gears 43 and splines 44 on the periphery for the entering of lock bolt 45, Figs. 2, 4 and 18. The indexing of the work spindle carrier, the operation of the chuck mechanism, the feeding of the stock are all interlocked mechanically and hydraulically. The hydraulic action will be described in the explanation of the hydraulic circuit diagram.

On the left face of the work spindle carrier is rigidly and concentrically fastened an indexing gear 46. On the chuck operating slide 21, Figs. 3 and 20, is a rack 21EL integral therewith. This chuck operating slide and rack have a longitudinal motion that is lengthwise of the machine in ways that are integral with and in fhe indexing slide 41, Figs. 1, 2, 3, 4, 18, 19 and 20. This indexing slide has a cross motion thaiI is from the front to the rear of the machine in ways in the index base II and receives its action through the piston rod 48b from the indexing piston 4l which is housed in the indexing base I. When all the tool slides are back ready for indexing the turret, the chuck operating piston 28 gets fluid under pressure which causes it to move to the right, causing the chuck slide 21 to move to the right, thereby opening the chuck and also causing the index rack 21l to move to the right,

'plunger 5|. which is integral with the index rack 21l and entering into mesh with indexing gear 46. When chuck piston 28 has finished this stroke, a port in its c linder wall is thereby opened, allowing theih under pressure to flow to in front of piston 48, causing the index piston to move back, taking the index slide 41 with it and also the chuck operating slide 21, which is mounted on index slide and which in turn carries the index rack 21. The work spindle carrier thereby is indexed. At the finish of the index stroke a port is opened in the cylinder wall of the index piston 48 and fluid under pressure is allowed to flow back to the right side of the chuck piston 28. The chuck piston then moves to the left sliding chuck thimble 25 to the right, thereby closing the chuck and also removing index rack 21a from index gear 45.

When this stroke is completed, the uid under pressure is allowed to flow to swinging gage stop, then to all the cross and turret tool slides and also back to the other end of index piston 48 where it causes the index piston to move towards the front of the machine, ready for the next index, this forward motion of index slides taking place while tool slides are on their forward stroke.

'Ihe stock feed has also taken place during this index. Mounted on the index slide 41 and moving with it is a stock feeding track cam 34 (see Figs. 1, 2, 3, 4, 18, 19 and 20). The stock feed Slide 33, Figs. 1, 2, 3, 4, 19 and 20, is mounted in ways on the index support and has a longitudinal motion only. A roll 33a on the stock feed cam is always in engagement with this cam 34. So the back and forth motion across the machine of the index slide 41. causes a longitudinal motion of the stock feed slide and stock feed shoe 32, Figs. 1, 2, 3, 4, 19 and 20, which shoe is integral with stock feed slide 33, Figs. 19 and 20. Hence, when the index slide is on the indexing stroke or towards the rear of the machine, the stock feed shoe will push stock feed tube into the spindle and the stock will be fed. At end of index as explained before, the stock is chucked so the return of index slide will return the stock feed slide and will pull the stock feed thimble 3| and stock feed fingers over the stock in spindle in lower front position. Then the stock feed mechanism will be ready for the next stock feeding.

The above mechanism will by the nature of hydraulics give a gradual acceleration to the indexing of the turret as well as a gradual acceleration to the feeding of the stock, both of which are important.

The gradual deceleration of the turret and the deceleration of the feeding of stock is taken care of by the placing of fluid cushions in the hydraulic circuit as shown on the hydraulic circuit, Figs. 15, A and 15B. The above indexing of turret, the feeding of the stock and chucking will be very rapid. If stock is oversize or other imperfection of stock occurs, there will be no excess strain and the machine will stop.

The work spindle carrier lock bolt mechanism also is operated by the indexing mechanism. As explained before, the work spindle carrier has splines in its periphery in which enters a lock bolt 45, Figs. 2, 4, 18, 19 and 20. 'Ihis lock bolt has a cross groove 458L in which the lock bolt is engaged by a lever 49 which is keyed to a shaft 45. At the left end of the shaft is keyed another lever 50 which is always in contact with spring 'I'his lever is engaged by` a cam 52 chuck slide 21. 'Ihe motion ol' the chuck slide 21 which moves the index rack 21* into mesh with the index gear 46 also moves the cam 52 into engagement with lock bolt lever 50 and pulls the wedge ready for indexing.

As the work spindle carrier is indexed, the spline 44, Fig. 18, moves away from the lock bolt and at the same time the cam 52 on index rack moves away from lock bolt lever 50, allowing lock bolt 45 to return, but the spline 44 has moved away so the lock bolt on its return cannot enter spline but comes to rest on the periphery of the work spindle carrier.

As the index is completed, the lock bolt actuated by the spring plunger 5| will snap into the next spline 44. There will be no shock to the work carrier as the index motion is gradually decelerated. At the end of index as explained before, the index rack leaves the index gear and hence on the return motion the index rack and cam 52 will not contact the lock bolt lever 50.

The main tool slide 10, Fig. 9, is of cylindrical form, which form can be machined accurately and is supported both by the work spindle carrier sleeve I4 and the bed bearing housing 3 and is moved axially by means of the tool slide piston 5 through the thrust washer 1|, Fig. 8. This thrust washer 1| is tapped to receive the tool slide piston 5. This thrust washer is held against the shoulder 12 in the tool slide by a mit 13 screwed in right end of tool slide. This construction eliminates the necessity of perfect alignment between tool slide and tool slide piston, because the circumference of washer 12 does not bear on bore of slide 10.

The tool slide 10, Fig. 9, is restrained from any rotation by means of two large keys or wedges 14 fastened in tool slide bearing housing 3 and bearing in longitudinal splines 15 milled parallel with axis of tool slide on periphery of tool slide. The front or left end of tool slide has also on its periphery for each tool two T-slots 1.6, Fig. 10, milled parallel with the axis of the tool slide for mounting the tool holder. In the tool holder ||I there is a key 18 that lits into T-slot 18 to keep holder in alignment. 'I'he tool slide is bored to receive the work spindle carrier sleeve I4 and the work spindle driving shaft l5.

'Ihe piston 5, Fig. 3, is slidable in its cylinder which is a sleeve which is lapped for a uid tight t with piston 5 and ground to make a fluid tight fit with the lapped bore in housing 4. The bore in cylinder sleeve 80, Fig. 3, is continued all the way through. In this bore at each end are cylinder ends 8| and 82 which fit tightly in the bore of the cylinder and are lapped to make a fluid tight bearing for the piston rods. The left cylinder end has a ange 83 that is held against cylinder sleeve 80 by a nut 84 that is threaded into housing 4. 'I'he right cylinder end has also a ange 85 that is held against cylinder 80 by a nut 85 that also holds cylinder sleeve 80 from any end motion.

'I'he right end of right cylinder end has a bored hole for drive shaft bearing 81. This construction eliminates the difficulty of grinding and lapping two different size diameters, that must be concentric in cylinder sleeve. This principle is used in the design of all pistons on the machine.

The cross slides unit, Figs. 10, 11, l2, 13 and 14, is composed of a base 40 that carries all the slides and their pistons 9| and throttle valves |04 as well as their other control apparatus as shown in Fig. 15A. The piping and connections are taken care of by ports and drilled and-cored Search Room holes in the housing or base 40 and in the details. The cross slides 90 are held in the housing 40 by plates 92 which are bolted to housing by screws 83.

The housing in Vurn is held against the work spindle carrier 2 and bed4 I by bolts 94. The tools 95 are held in suitable holders which are in turn held in grooves in cross slides. Each slide is propelled by a piston 9| through a piston rod 96 which has a milled slot 91 into which is tted a pin 98, the end of which is machined to fit the slot in the piston rod 96.

The piston rod fits in a hole B9 in the cross slide 90 so that it will not spring. The pin 98 is fitted securely into the cross slide. The movement of the piston therefore causes a movement of the cross slide.

On the work spindle carrier I3 are cast integral lugs |00, one for each spindle, into each of which are threaded radially two cross slide stop screws ||EL and |0|b, one for the lower front and upper rear and the other for the upper front and lower rear cross slides. These screws stop the forward or cutting motion of the cross slides and are adjustable to compensate for variation in the location of the several spindles. On each cross slide is a long stop screw |02 that engages with one of the stop screws |0|a and |0|b. This limits the forward motion of the cross slides, serving for a micrometer stop for obtaining accurate diameters, as is readily understood. Also the limiting of the forward motion causes a decrease in the hydraulic pressure at the right end of cross slide piston, causing the slides to return as will be shown fully in the explanation of the hydraulic circuit.

The cross slides move forward into rapid traverse until the cam 03 mounted on cross slide, Figs. 11, 13 and 14, contacts with cross slide throttle valve plunger |04 which it depresses and causes the return iiuid to be throttled and to flow at the feed rate. The amount of feed rate is determined by the height of the cam |03 which is adjustable up and down for rate of feed and is slidable along in T-slots |05 located in the cross slide in order to regulate the place in the forward stroke when the slide should drop into the feed rate.

Fitting into the T-slot so as not to turn is a nut |06 in which is threaded a clamp screw |01 which clamps cam 03 and sliding block |08 to cross slide. This sliding block has a tongue that fits into a vertical groove in cam |03 giving motions to cam in a vertical or horizontal direction. An adjusting collar screw |09 will give a fine up-and-down or feed adjustment to the cam.

The hydraulic cushioning of all the slides and valves at the end of both the forwarding and returning strokes is the same in principle in all cases and is merely a trap for fluid with a variable V-notch escape that is automatically diminished as the piston approaches the end of the stroke. This trap is made by having a reduced diameter on the piston that :lits closely in a reduced cylinder bore. The V-notches shown on Figs. 15, 15A and 15B on all pistons are preferably made on the piston. There are two, diametrically opposite, in order that the valve will be balanced, that is that there will be equal pressures all around the piston and valves.

The feed and chuck thimbles are indexed out of and into the feed and chuck thimble retainers H5* and Ilt'h and IIB and |||ib which are integral with guards II5c and |I.id and IIE and IIBd pivoted on rod ||8 and held from movement by work spindle housing 2 and sleeve II! pinned on rod ||8, Figs. 3, 18 and 19. By lifting these guards, the chucks can be opened and closed by hand with a suitable lever. Retainers I'I and H6 and guards ||5d and I|6d are in front and used for the chuck and feed thim-v ble, respectively.

The swinging gage stop |20, Fig. 10, is clamped to and pivoted on a preferably hexagonally shaped shaft |2|. By loosening clamp screws |20, the stop can be slid along shaft |2| for regulating length of stock feed. Another lever |22 located within cross slide housing 40 is pinned to this shaft I2|. This lever has a projection |23 which extends in between two collars |24 of hydraulic piston |25. The piston thereby rotates the swinging gage stop into position for gaging the length of stock before index. It remains in position during index and returns out of the way of the tools after index and before any of the tools start forward.

The general cross slide arrangement eliminates levers, cams, overhang of slides and the accompanying vibration. It not only gives rigidity, ease of adjustment of tools, but also allows more light to reach the tools and better escape of the chips. There will also be little splash of cooling substance.

The pumps and work spindles are started and stopped by means of a push button |30 in front of the machine, Fig. 1. The movement of all slides and index of the machine is fully and conveniently controlled by feed valve I3I which is operated by handle |32.

The motor A, Fig. 2, drives through a chain belt |35, the change gear shaft and change gears |31 and |38 in turn drive the work spindles through center drive shaft I5 and any attach'- ments through the gear 38* located next to driven change gear |33. The double pump B-C for the hydraulic circuit is directly driven by the motor A. The pump E (Fig. 3) for the cooling substance is driven through a chain |36. Both pumps and motor are mounted on a motor base |31 which is supported by two shafts or rods |58, Figs. 2, 3 and 6, which are held in bored holes in the bed casting. All piping is either inside of the bed or is eliminated by cored and drilled holes in the details. The cooling substance does not reach intake pipe of pump directly from chip space but must take a long path to opening |40, Fig. 3, at left end of bed and then back through passageway or conduit III, Figs. 3 and 4, in bed. thereby allowing time for cooling substance to deposit the foreign matter held in suspension and to lose some of its heat before being used again.

The hydraulic circuit, Figs. 15, 15A and 15B. is of the orifice or look circuit type which controls the return circuit and not the input. This makes for positive control overcoming the inertia of the parts, one of the important features of the circuit being the interlocking of all the hydraulic slides so that they are made to synchronize. This is done by preventing the starting of one set of operations before another is completed.

The indexing of the work spindle turret I3', the opening and closing of the chuck thimbles 25 and the feeding of the stock and the operation of the gage stop cannot take place until each and every tool slide has finished cutting and has returned out of the way of the work during index. This is obtained by running a pilot circuit I around through all the tool slides units. 

